Modern Britain scratches its head over children who are overfed, not underfed, while guilt-ridden mothers stand accused of feeding children badly even if they are not obese. These are not insignificant troubles since childhood obesity is set to cost the NHS many millions in years to come. But as a new exhibition at the Foundling Museum in London will show, infant and child nutrition is not a new science and the challenge of nurturing, not least keeping children alive before the age of five, was taken just as seriously two centuries ago as it is now.